Pictorial Supplement to The Fifth Kingdom - Chapter 17

Mycorrhizae - mutualistic plant-fungus symbioses
(35 pictures)
(the CD-ROM has full text and 46 pictures)

[grateful acknowledgment to S. Berch, C. Godbout, M. Brundrett, 
D. Malloch & J.M. Trappe
who generously made some of these 
images available to me for teaching purposes]

(1) Ectomycorrhizas

mrz1.jpg (6785 bytes) dichotomously branched ectomycorrhizas of a basidiomycete with a conifer.
    X 4
mrz2.jpg (8280 bytes) ectomycorrhizas of Suillus subluteus with Pinus resinosa (the branched ends of the short lateral roots)
    X 2/3
mrz4.jpg (6200 bytes) dichotomous ectomycorrhizas (upper) and mycelial strands (lower) of Amanita muscaria on Pinus strobus.
mrz3.jpg (7546 bytes) ectomycorrhizas of Laccaria bicolor with Populus tremuloides.
   
X 3
mrz5.jpg (8620 bytes) transverse section of an ectomycorrhiza of Pseudotsuga menziesii with Rhizopogon colossus showing the fungal mantle (brown in this example).
    X 50
mrz6.jpg (9278 bytes) section of outer layers of an ectomycorrhizal root of Pinus strobus, showing some of the mantle and the Hartig net - the latter formed by hyphae of  the mycobiont, Pisolithus tinctorius, penetrating between the cortical cells of the root.
mrz7.jpg (5773 bytes) Ectomycorrhizas - a root cell completely surrounded by hyphae of the Hartig net.
mrz8.jpg (8914 bytes) mantle of an ectomycorrhiza of Populus tremuloides in section and Hartig net in surface view - the section was cleared then stained with chlorazol black E.  The fungus is stained dark brown. Viewed with interference contrast.  (see Fig 52 in Brundrett et al. 1990. Can. J. Bot. 68: 551).
mrz9.jpg (5007 bytes) surface view of the uniquely branched and contorted hyphae of the Hartig net filling the space between cells of the root cortex of an ectomycorrhiza.
mrz10.jpg (7295 bytes) seedlings of Douglas fir with and without ectomycorrhizal partners.
mrz11.jpg (10724 bytes) bisected basidioma of Pisolithus tinctorius, an important ectomycorrhizal fungus, showing the gleba divided up into locules, and the yellow pigment in the base.
          (2) Endomycorrhizas (Arbuscular Mycorrhizas)
mrz14.jpg (5847 bytes) a part of the "extramatrical" mycelium of Glomus mosseae, an endomycorrhizal fungus grown in leek roots in a root chamber. The sand around the roots has been carefully rinsed away, and the material cleared then stained with chlorazol black E (M. Brundrett)
mrz15.jpg (5489 bytes) as above, but showing monosporic sporocarps of Glomus mosseae with hyphal peridium. (M. Brundrett)
mrz16.jpg (5119 bytes) long  and short cells in the dimorphic exodermis of Smilacina racemosa.  The short cells remain unsuberized longer, and permit entry of endomycorrhizal fungi.  Five of the 8 short cells shown here have been colonized. (see Fig 39 in Brundrett & Kendrick 1990  New Phytol. 114: 469)
mrz17.jpg (10726 bytes) penetration pattern of Glomus versiforme, an endomycorrhizal fungus, into a leek root. Note that arbuscules are formed in cells of the cortex, and that the fungus does not penetrate the stele. (see Fig 20 in Brundrett et al. 1985 Can. J. Bot. 63: 184)
mrz18.jpg (13699 bytes) a stained arbuscule of Glomus mosseae in a leek root cell (a superb photomicrograph by Mark Brundrett - see Fig 17 in Brundrett et al. 1984 Can. J. Bot. 62: 2128)
mrz19.jpg (5138 bytes) hyphae and arbuscules of an endomycorrhizal fungus in Asarum (wild ginger) (see Fig 15 in Brundrett & Kendrick 1988 Can. J. Bot. 66: 1153)
mrz20.jpg (8097 bytes) colonization of a root by an endomycorrhizal fungus. Note hyphae, arbuscules and vesicles.  (see Fig 21 in Brundrett et al. 1985 Can. J. Bot 63: 184)
mrz21.jpg (5539 bytes) a later stage of colonization.  The arbuscules contract and degenerate, and more vesicles develop.
mrz22.jpg (6141 bytes) a leek root packed with vesicles of its endomycorrhizal fungal partner.
mrz25.jpg (6594 bytes) these structures in the "roots:" of early land plants fossilized in the Rhynie Chert (350 MYBP) are regarded as vesicles of an early endomycorrhizal fungus.
mrz23.jpg (6046 bytes) endomycorrhizas - extramatrical spores of Glomus versiforme (M. Brundrett).
endomycorrhizas - a single extramatrical spore of Glomus mosseae (M. Brundrett)
mrz26.jpg (7881 bytes) section of a sporocarp of Glomus, an endomycorrhizal fungus.
mrz27.jpg (81204 bytes) the "big plant - little plant" experiment showing the benefits of the endomycorrhizal symbiosis (plants on the right are not mycorrhizal).
mrz28.jpg (6504 bytes) Endogone pisiformis fruiting on Sphagnum in a bog.   The yellow sporocarp contains a very large number of zygosporangia (below).   Though formerly recognized as the type genus of endomycorrhizal fungi, Endogone is now known to be ectomycorrhizal.
mrz30.jpg (3612 bytes) a single zygosporangium of Endogone pisiformis.  Note the two suspensors,
          (3) Arbutoid mycorrhizas (Ectendomycorrhizas)
mrz31.jpg (5554 bytes) Arbutoid mycorrhizas of Arbutus menziesii with Lactarius deliciosus.
mrz32.jpg (8011 bytes) Transverse section of arbutoid mycorrhiza of Arbutus menziesii with Lactarius deliciosus.  Note mantle, and cortical cells filled with hyphae.
mrz33.jpg (7774 bytes) Arbutoid mycorrhiza - high power view of part of section shown above.
                                      (4) Ericoid mycorrhizas
mrz35.jpg (4536 bytes) ericoid mycorrhiza of salal, Gaultheria shallon. Dark blobs are masses of fungal hyphae in cortical cells of root.
mrz34.jpg (9615 bytes) transverse section of ericoid mycorrhiza of salal, Gaultheria shallon.
                                     (5) Monotropoid mycorrhizas
mrz36.jpg (9975 bytes) section of part of a monotropoid mycorrhiza of Monotropa uniflora.  Note the diagnostic peg-like hypha penetrating a root cell (indicated by arrowhead).
                               (6) Orchid mycorrhizas
orchid mycorrhiza1.jpg (5979 bytes) root cells of Goodyera oblongifolia containing coils (pelotons) of hyphae (probably of a mycorrhizal Rhizoctonia).
orchid mycorrhiza3.jpg (7242 bytes) Goodyera cells again: note two distinct constrictions in the fungal hyphae where they penetrate from one cell to the next.
For more information on mycorrhizas and more pictures, visit this site:
http://mycorrhiza.ag.utk.edu/
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Mycologue Publications 2001